Conventional methods for making copper wire involve the following steps. Electrolytic copper (electrorefined, electrowon, or both) is melted, cast into bar shape, and hot rolled into a rod shape. The rod is then cold-worked as it is passed through drawing dies that systematically reduce the diameter while elongating the wire. In a typical operation, a rod manufacturer casts the molten electrolytic copper into a bar having a cross section that is substantially trapazoidal in shape with rounded edges and a cross sectional area of about 7 square inches. This bar is passed through a preparation stage to trim the corners, and then through 12 rolling stands from which it exits in the form of a 0.3125" diameter copper rod. The copper rod is then reduced to a desired wire size through standard drawing dies. Typically, these reductions occur in a series of dies with a final annealing step and in some instances intermediate annealing steps to soften the worked wire.
The conventional method of copper wire production consumes significant amounts of energy and requires extensive labor and capital costs. The melting, casting and hot rolling operations subject the product to oxidation and potential contamination from foreign materials, such as refractory and roll materials, which can subsequently cause problems to wire drawers which include wire breaks during drawing.
By virtue of the inventive process, copper wire is produced in a simplified and less costly manner when compared to the prior art. The inventive process utilizes electrodeposited cathodic copper as the copper source, and thus does not require use of the prior art steps of melting, casting and hot rolling to provide a copper rod feedstock.
U.S. Pat. No. 440,548 discloses a method for making wire which comprises electrodepositing a shell or cylinder of copper on a core, mold or mandrel; removing the deposited copper from the core, mold or mandrel using thermal expansion/contraction, or the rotary motion of a lathe coupled with the pressing movement of a roller; mounting the removed shell or cylinder of deposited copper in a machine for the purpose of cutting the shell or cylinder circumferentially into a continuous strip or rod; and drawing the strip or rod to form wire.
U.S. Pat. No. 4,771,519 discloses an apparatus for manufacturing a thin metal strip from a cylindrical metal workpiece that includes a rotatable workpiece support structure for concentrically mounting the workpiece, drive means for rotating the workpiece about its axis, holder means for supporting a cutting tool adjacent the peripheral surface of the cylindrical workpiece on the workpiece support structure, a cutting tool secured in the holder means, the cutting tool having a sharpened edge that is defined in part by a rake face that has a length of less than one millimeter, feed means for advancing the sharpened edge of the cutting tool transversely of the axis of the workpiece to peel a continuous thin metal strip from the workpiece, strip tensioning means for subjecting the strip to tension as it is peeled from said workpiece, and strip direction control means between the cutting tool and the strip tensioning means for varying the strip exit angle of the tensioned strip relative to the rake face of the cutting tool as the strip is being peeled from the workpiece.
U.S. Pat. No. 5,516,408 discloses a process for making copper wire directly from a copper-bearing material, comprising: (A) contacting said copper-bearing material with an effective amount of at least one aqueous leaching solution to dissolve copper ions into said leaching solution and form a copper-rich aqueous leaching solution; (B) contacting said copper-rich aqueous leaching solution with an effective amount of at least one water-insoluble extractant to transfer copper ions from said copper-rich aqueous leaching solution to said extractant to form a copper-rich extractant and a copper-depleted aqueous leaching solution; (C) separating said copper-rich extractant from said copper-depleted aqueous leaching solution; (D) contacting said copper-rich extractant with an effective amount of at least one aqueous stripping solution to transfer copper ions from said extractant to said stripping solution to form a copper-rich stripping solution and a copper-depleted extractant; (E) separating said copper-rich stripping solution from said copper-depleted extractant; (F) flowing said copper-rich stripping solution between an anode and a cathode, and applying an effective amount of voltage across said anode and said cathode to deposit copper on said cathode; (G) removing said copper from said cathode; and (H) converting said removed copper from (G) to copper wire at a temperature below the melting point of said copper. In one embodiment the copper that is deposited on the cathode during (F) is in the form of copper foil, and the process includes (H-1) slitting the copper foil into a plurality of strands of copper wire and (H-2) shaping the strands of copper wire to provide said strands of copper wire with desired cross-sections. In one embodiment the copper that is deposited on the cathode during (F) is in the form of copper powder, and the process includes (H-1) extruding the copper powder to form copper rod or wire and (H-2) drawing the copper rod or wire to form copper wire with a desired cross-section. In one embodiment, during step (G) the copper while on said cathode is score cut to form a thin strand of copper which is then removed from the cathode, and during step (H) this thin strand of copper is shaped to form copper wire with a desired cross-section.